Respuesta :

3/4 of an hour is 45 minutes and 7/12 of an hour is 35 so 

45+35= 80minues if 60 minutes is an hour then its 1 hour and 20 minutes.

3/4 = 9/12

9/12 + 7/12 = 16/12 = 1 4/12 = 1 1/3 hours